Although patient reminder/recall systems have been shown to be effective at improving vaccination coverage levels for infants and younger children, little is known about the effectiveness of such systems for increasing immunization rates in adolescent populations. The process of reminder/recall in adolescents, and vaccination of adolescents overall, presents particular challenges. Adolescents are less likely to routinely access health care compared to younger children and adults. In addition, other obstacles such as lack of health insurance, missed opportunities for vaccination during health care visits, and the scattering of immunization records across multiple providers have posed major challenges in the vaccination of adolescents. Issues of parental consent for vaccination can also be problematic, given that adolescents may present for care without their parents accompanying them. These and other barriers to immunization may reduce the effectiveness of reminder/recall for adolescents. In the current proposal, a study team with extensive experience in immunization delivery research will investigate the ability of pediatricians and family physicians in a number of different practice settings to implement a reminder/recall system for their adolescent patient populations. The study will include seven types of clinical settings including pediatric and family medicine practices, urban and rural practices, community health clinics and managed care organization sites. In addition, we will be able to examine the effectiveness of reminder/recall originating at public school-based health centers, an innovative strategy that has not previously been reported. Randomized controlled trials of reminder recall for adolescents will be conducted at each type of site, with randomization at the level of the patient. The study team will track important process measures during reminder/recall including the percentage of eligible population who actually received intervention;percentage with incorrect addresses;percentage with incorrect or disconnected phones;percentage with up-to-date vaccinations but incorrectly recalled;missed vaccination opportunities;and invalid doses of vaccines administered. In this way, we will be able to not only determine the degree to which reminder/recall was successful for adolescents, but also identify impediments to success, which will provide a foundation for future efforts. Our study will also investigate the cost of establishing and operating a reminder/recall system for adolescents in each type of clinical setting. Finally, in two practices we will examine parental attitudes regarding patient-directed reminder/recall in which parents select their preferred method of contact, including such innovative methods as text messaging using cellular telephones or e-mail reminders. Although patient reminder/recall systems have been shown to be effective at improving vaccination coverage levels in young children, little is known about the effectiveness of such systems for increasing immunization rates in adolescents, a population in which several new vaccines have recently been recommended. This large randomized controlled trial will examine the effectiveness of reminder/recall for adolescents in seven different types of practice settings including pediatric and family medicine private practices, community health clinics, health maintenance organization settings, rural settings and school-based health centers. The study will provide important information to guide future public health efforts to achieve high rates of immunization in adolescents.